Interference mitigation in distributed antenna systems

ABSTRACT

In an example, a distributed antenna system (DAS) includes a central unit configured to be coupled to a base station and the central unit is configured to receive downlink signals from the base station. The central unit is also configured to support a plurality of transmission bands and a plurality of receiver bands. The DAS further includes a plurality of remote units configured to communicate wireless signals in a coverage area of the distributed antenna system, and the plurality of remote units are communicatively coupled to the central unit and located remotely from the central unit. The DAS is configured to mitigate interference using dynamic allocation of at least one of the plurality of transmission bands and/or at least one of the plurality of receiver bands among the plurality of remote units.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/831,226, filed Dec. 4, 2017, and titled “Unequal Transmitter andReceiver Distribution in Distributed Antenna System,” which is acontinuation of U.S. patent application Ser. No. 14/694,191, filed Apr.23, 2015, and titled “Unequal Transmitter and Receiver Distribution inDistributed Antenna System,” which claims priority to U.S. ProvisionalApplication Ser. No. 61/983,672, filed Apr. 24, 2014, and titled“Unequal Transmitter and Receiver Distribution in Distributed AntennaSystem,” the contents of all of which are incorporated herein byreference.

BACKGROUND

A telecommunications system, such as a distributed antenna system (DAS),can include one or more central units and multiple remote units coupledto each central unit. A DAS can be used to extend wireless coverage inan area. Central units can be coupled to one or more base stations thatcan each manage wireless communications for different cell sites.Central units can be controllers that perform the role of, or arecoupled to, base stations, as well as provide other control and signaldistribution functions. A central unit can receive downlink signals fromthe base station and distribute downlink signals in analog or digitalform to one or more remote units. The remote units can transmit thedownlink signals to user equipment devices within coverage areasserviced by the remote units. In the uplink direction, signals from userequipment devices may be received by the remote units. The remote unitscan transmit the uplink signals received from user equipment devices tothe central unit. The central unit can transmit uplink signals to theserving base stations.

SUMMARY

In one aspect, a distributed antenna system is provided. The distributedantenna system can include a first set of remote units configured fortransmitting wireless signals in a coverage area. The distributedantenna system can also include a second set of remote units configuredfor receiving wireless signals from the coverage area. The number of thefirst set of remote units is different from the number of the second setof remote units. The distributed antenna system can also include acentral unit configured for communicatively coupling to the first set ofremote units and the second set of remote units. The central unit isalso configured for communicatively coupling to a base station.

In another aspect, a distributed antenna system is provided. Thedistributed antenna system can include a central unit configured forcommunicatively coupling to a first set of remote units and a second setof remote units. The central unit also supports one or more transmittingbands and one or more receiving bands. The first set of remote units canbe configured to utilize a first subset of the transmitting bands. Thesecond set of units can be configured to utilize a second subset of thereceiving bands. The subset of the transmitting bands is different innumber than the subset of receiving bands.

In another aspect, a method is provided. The method can includetransmitting, by a central unit, downlink signals to a first set ofremote units. The method can also include transmitting, by the first setof remote units, the downlink signals to a coverage area. The method canfurther include receiving, at the central unit, uplink signalstransmitted by user equipment devices from a second set of remote units.The first set of remote units is different in number from the second setof remote units.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example of a distributed antenna system(DAS) with a central unit and a network of remote units according to oneaspect of the present disclosure.

FIG. 2 is a block diagram of an example of a configuration of a DAS witha greater number of receivers than transmitters according to one aspectof the present disclosure.

FIG. 3 is a block diagram of an example of a configuration of a DAS witha greater number of transmitters than receivers according to one aspectof the present disclosure.

FIG. 4 is a block diagram of an example of a configuration of a DAS withprimary remote units and secondary remote units according to one aspectof the present disclosure.

FIG. 5 is a block diagram of an example of a configuration of a DAS withremote units organized in clusters according to one aspect of thepresent disclosure.

FIG. 6 is a block diagram of an example of a configuration of a DAS witha transmitter remote unit integrated into the circuitry of a centralunit according to one aspect of the present disclosure.

FIG. 7 is a block diagram of an example of a configuration of a DAS witha transmitter remote unit attached to or co-located with a central unitaccording to one aspect of the present disclosure.

FIG. 8 is a signal diagram of allocating frequency bands as transmissionfrequency bands and receiver frequency bands according to one aspect ofthe present disclosure.

FIG. 9 is a block diagram showing an example of a DAS with remote unitsallocated the different frequency bands that are shown in FIG. 8according to one aspect of the present disclosure.

FIG. 10 is a flowchart depicting an example of a process forcommunicating signals in a DAS with an unequal distribution oftransmitters and receivers according to one aspect of the presentdisclosure.

FIG. 11 is a schematic diagram depicting an example of a remote unitconfigured as a receiving remote unit according to one aspect of thepresent disclosure.

FIG. 12 is a schematic block diagram depicting an example of a remoteunit configured as a transmitting remote unit according to one aspect ofthe present disclosure.

DETAILED DESCRIPTION

Certain aspects and features of the present disclosure relate to adistributed antenna system (DAS) with an unequal distribution oftransmitters and receivers. For example, the DAS can include a number oftransmitting remote units, a number of receiving remote units, and acentral unit. The number of transmitting remote units can be differentfrom the number of receiving remote units such that the DAS includes anunequal number of transmitters and receivers. Transmitting remote unitscan be used to transmit downlink wireless communication signals from thecentral unit to user equipment devices within respective coverage zonesof the transmitting remote units. Receiving remote units can be used toreceive uplink communication signals transmitted by the user equipmentdevices. Receiving remote units can transmit the uplink communicationsignals to the central unit. The central unit can combine the uplinkcommunication signals from the receiving remote units and transmit thecombined uplink communication signal to the cellular base station.Transmitting remote units may transmit downlink wireless communicationsignals but not receive uplink communication signals. Similarly,receiving remote units may receive uplink communication signals but nottransmit downlink communication signals.

A DAS with an unequal distribution of transmitters and receivers canalso be obtained by allocating carrier frequency bands unequally amongremote units that are capable of transmitting and receiving wirelesssignals. Remote units, which may support multiple frequency bands, mayuse different combinations of transmission frequency bands or receiverfrequency bands.

A DAS having more transmitters than receivers, for example, may providebetter signal transmission performance in transmitting signals to themobile user equipment, allowing for downlink capabilities at higherspeeds. A DAS with more transmitters than receivers can also utilizelower-power transmitters, but more transmitters, to minimize heat,power, fan, or audible noise concerns. Further, as high receiversensitivity can be less important in an indoor, short distanceenvironment, fewer receivers may be used. Alternatively, having fewer,higher-power transmitters may be advantageous in some circumstances byallowing for higher-power transmitters to take advantage of transmittertechniques that are more efficient. Unequal transmitter and receiverdistribution in DAS can also spread out receivers to minimize path lossto any particular mobile user equipment. This can allow the mobile userequipment to retain low transmit power, which can improve battery lifeand decrease interference. Unequal transmitter and receiver distributionin DAS may also help reduce leakage to outside cell sites.

Further, unequal transmitter and receiver distribution in a DAS canallow for allocating different frequency bands to the transmittingremote units and the receiving remote units. In some aspects, differentsubsets of frequency bands can be allocated as transmission bands andreceiver bands unequally among the remote units. In other aspects,allocating different frequency bands can provide different levels ofMultiple-Input-Multiple-Output (MIMO) compatibility in the DAS. Forexample, in a DAS with six transmitting remote units, four of thetransmitting remote units can transmit signals in one MIMO band and twoof the transmitting remote units can be configured to transmit signalsin a second MIMO band.

These illustrative examples are given to introduce the reader to thegeneral subject matter discussed here and are not intended to limit thescope of the disclosed concepts. The following sections describe variousadditional aspects and examples with reference to the drawings in whichlike numerals indicate like elements, and directional descriptions areused to describe the illustrative examples but, like the illustrativeexamples, should not be used to limit the present disclosure.

FIG. 1 is a block diagram depicting an example of a DAS 100 that isdesigned to transport wireless communication between a base station 114and user devices positioned in coverage zones 110, 112. The DAS 100 caninclude a network of spatially separated remote units 104, 106 a-bcommunicatively coupled to a central unit 102 (e.g., a head-end unit ora repeater). The central unit 102 can communicate information, data, andsignals between the base station 114 and the remote units 104, 106 a-b.The remote units 104, 106 a-b can provide signal coverage to userequipment devices located in respective coverage zones 110, 112. Incertain aspects and features, remote units 104, 106 a-b can beconfigured as transmitting remote units or receiving remote units sothat there is unequal distribution of transmitters and receivers in theDAS 100.

For illustrative purposes, FIG. 1 depicts a DAS 100 that communicateswith one base station 114 and that includes a single central unit 102and three remote units 104, 106 a-b serving two coverage zones 110 and112. A DAS according to various other examples can communicate with anynumber of base stations and can include any suitable number of centralunits and remote units. A DAS can also serve any number of coveragezones.

The central unit 102 can receive downlink signals from a base station114 and transmit uplink signals to the base station 114. Any suitablecommunication link can be used for communicating between the basestation 114 and the central unit 102. For example, a wired link or awireless link can be used for communication between the base station 114and the central unit 102. A wired link can include, for example, a cablethat is copper, optical fiber, or other suitable communication medium.In some aspects, the central unit 102 can include an external repeateror internal RF transceiver to communicate with the base station 114. Insome aspects, the central unit 102 can combine downlink signals receivedfrom different base stations 114. The central unit 102 can transmit thecombined downlink signals to one or more of the remote units 104, 106a-b.

Remote unit 104, 106 a-b can be configured as transceiver remote unitsthat can both transmit and receive signals wirelessly with the centralunit 102. Each transceiver remote unit can include both a transmitterand a receiver. When remote units 104, 106 a-b are configured astransceiver remote units, unequal transmitter/receiver distribution inthe DAS can be obtained by allocating certain transmission frequencybands and receiver transmission bands to the transceiver remote units.In other aspects, each remote unit 104, 106 a-b may include either atransmitter or a receiver, but not both. Separating the transmitters andreceivers may be achieved by splitting the transmitter/receiver pairs ofeach transceiver for the remote units 104, 106 a-b.

The remote units 104, 106 a-b that are configured as transmitting remoteunits can provide signal coverage in coverage zones 110 and 112 bytransmitting downlink signals to user equipment devices. The remoteunits that are configured as receiving remote units can receive uplinksignals from the user equipment devices and transmit the uplink signalsto the central unit 102. The central unit 102 can combine uplink signalsreceived from the remote units 104, 106 a-b configured as receivingremote units, for transmission to the base station 114.

The remote units 104, 106 a-b can be communicatively coupled to thecentral unit 102 via any suitable digital communication link. Forexample, a digital communication link can include a 10GBASE-T Ethernetlink. In some aspects, the Ethernet link can include a wired link suchas copper cabling, optical fiber, or coaxial cable. In additionalaspects, the Ethernet link can include a wireless link. Each remote unit104, 106 a-b may be independently coupled to the central unit 102. Orseparate transmitters and receivers can be coupled together and to thecentral unit 102 in a daisy-chain fashion.

A DAS can include varying numbers of transmitting remote units andreceiving remote units. Many configurations of unequal receiver andtransmitter distribution in the DAS 100 are possible. FIGS. 2 through 9illustrate various possible configurations for implementing unequaltransmitter and receiver distribution in a DAS. Although single antennaor single-input-single-output (SISO) transmitters and receivers arediscussed and shown in the diagrams herein, each transmitter or receiverremote unit discussed in the figures below may be a MIMO transmitter ora MIMO receiver having multiple independent transmitters or receivers(with or without multiple antennae). The subject matter described hereinmay also apply to MIMO configurations and are not limited to SISOinstallations or approaches.

For example, FIG. 2 is a block diagram of a DAS in which there are morereceiving remote units than transmitting remote units. FIG. 1 depicts acentral unit 202 communicatively coupled to nine receiving remote units204 a-i and to four transmitting remote units 206 a-d. The receivingremote units 204 a-i and transmitting remote units 206 a-d areseparately and directly coupled to the central unit 202. By beingseparately and directly coupled to the central unit 202, each receivingremote unit 204 a-i and transmitting remote unit 206 a-d is coupled tothe central unit 202 without any intermediate communication device inbetween the signal path of the respective remote unit and the centralunit 202. In other configurations, each receiver remote unit 204 a-i andtransmitter remote unit 206 a-d can be indirectly coupled to the centralunit 202. For example, each receiver remote unit 204 a-i and eachtransmitter remote unit 206 a-d can be communicatively coupled to thecentral unit 202 via one or more intermediate communications devices,such as an expansion access node (not shown).

Each receiver remote unit 204 a-i and each transmitter remote unit 206a-d can include an antenna component and a circuitry component. Thecircuitry component and the antenna component can be physicallyseparated and communicatively coupled (e.g., connected via acommunications link) or can be integrated or co-located in a sharedphysical device.

Similarly, FIG. 3 depicts a block diagram of a DAS having moretransmitters than receivers. Specifically, FIG. 3 depicts a central unit302 communicatively coupled to four receiving remote units 304 a-d andnine transmitting remote units 306 a-i. Similar to the receiving remoteunits 204 a-i and the transmitting remote units 206 a-d shown in FIG. 2,the receiving remote units 304 a-d and transmitting remote units 306 a-ican be separately and directly coupled to the central unit 302.Separating receivers from transmitters, as shown in FIGS. 2 and 3, mayimprove signal isolation, allow for improved power output, or allow formore flexibility. Combining receivers and transmitters together canimprove ease of installation and reduce system cost.

In other configurations, the remote units may be divided into differenttypes. For example, FIG. 4 depicts a block diagram of a central unit 402communicatively or directly coupled with primary remote units 404 a-d.Primary remote units 404 a-d may include both a transmitter and receiverand thus operate as both transmitting remote units and receiving remoteunits. “Secondary” remote units may include just a receiver or just atransmitter and thus operate is either receiving remote units or atransmitting remote units. The primary remote units 404 a-d can becommunicatively or directly coupled to secondary remote units 406 a-d.FIG. 4 depicts a greater number of transmitting remote units thanreceiving remote units. The secondary remote units 406 a-d can utilizethe same full signal processing as the primary remote units 404 a-d, orthe secondary remote units 406 a-d can utilize less processing or becontrolled and fed from primary remote units 404 a-d. The four secondaryremote units 406 a-d are configured as transmitting remote units.Secondary remote units can also be configured, however, as receivingremote units.

In another configuration, each remote unit may include a single receiverand one or more transmitting remote units coupled in a fixed, non-fixed,or variable radius. In this configuration, a variable number of remoteunits of a first type (e.g., transmitter or receiver) and a variablenumber of remote units of a second type (e.g., transmitter or receiver)can form a “cluster,” allowing the transmitting and receiving remoteunits to be coupled to the central units in clusters. The “cluster”formed by the one or more transmitting remote units coupled to eachreceiving remote unit (or vice versa) may allow for an unequal number ofreceiving remote units and transmitting remote units in the DAS. Eachcluster can include a central, node remote unit that forms the center ofa cluster. Each node remote unit can be coupled to both the central unitand to one or more member remote units, which can also be eitherreceiving remote units or transmitting remote units.

For example, FIG. 5 depicts an example of a configuration of a centralunit 502 communicatively or directly coupled with node remote units 504a-d. The four node remote units 504 a-d are shown configured asreceiving remote units that form the center of the clusters 510 a-d,respectively. The four illustrated node remote units 504 a-d can furtherbe communicatively or directly coupled to a variable number of memberremote units 506 a-i. Member remote units 506 a-i are configured astransmitting remote units. The member remote units 506 a-i of clusters510 a-d are of the opposite type as the node remote units 504 a-d (e.g.,transmitter member units are coupled to a receiver node remote unit ineach cluster). In other aspects, node remote units can be configured astransmitting remote units while member remote units are configured asreceiving remote units. The configuration shown in FIG. 5 may simplifyinstallation of the remote units. This configuration can also beimplemented using single transmitters with one or multiple receivingremote units.

In another configuration, the DAS may include a single, centrallylocated transmitter remote unit for transmitting signals to userequipment. The centrally located transmitter remote unit can be coupledto multiple receiving remote units that are distributed over a coveragearea. For example, FIG. 6 depicts a DAS including a central unit 602with an integrated transmitter remote unit 606. The central unit 602 canbe communicatively coupled with multiple receiving remote units 604 a-d.While the single transmitter remote unit 606 can be coupled within thecircuitry of the central unit 602, the four receiving remote units 604a-d can be remotely located from the central unit 602 and can be eachindependently coupled to the central unit 602. In such a configuration,the central unit 602 can transmit downlink signals to user equipmentdevices via the integrated transmitter remote unit 606. Uplink signalsfrom user equipment devices can be received by receiving remote units604 a-d, which can then provide the uplink signals to central unit 602.Central unit 602 can combine the uplink signals from remote units 604a-d and transmit the combined uplink signals to a base station.

While FIG. 6 depicts a centrally located transmitter remote unit 606,the DAS configuration may include a single, centrally located receiverremote unit that is coupled to multiple transmitting remote units. Ineither configuration, the centrally located remote unit can beintegrated into the circuitry of the central unit.

In other aspects, a centrally located remote unit can be attached to orco-located with a central unit without being integrated into thecircuitry of the central unit. For example, FIG. 7 depicts a blockdiagram of a central unit 702 with a single transmitter remote unit 704that is attached or co-located with the central unit 702. The centralunit 702 can provide downlink signals to the transmitter remote unit704, which can transmit the downlink signals to user equipment devices.Remote units 706 a-d can receive uplink wireless signals from the userequipment devices and provide the uplink signals to the central unit702.

Another approach for implementing unequal transmitter and receiverdistribution in a DAS is to allocate transmitter and receiver frequencybands unequally among the remote units. The remote units, which maysupport multiple frequency bands, may also support differentconfigurations of transmitter and receiver bands or sub-bands. Forexample, FIG. 8 depicts the division of frequency bands in an example ofa frequency spectrum that can be used in a DAS. In one example, afrequency spectrum can be divided into different subsets of supportedfrequency bands for transmission bands and receiver bands. The supportedtransmission bands of a transmitting remote unit are shown in the upperportion of the diagram 810 and the supported bands of a receiving remoteunit are shown in the lower portion of the diagram 820. The subset ofsupported transmission bands can be different from the subset ofreceiver bands. FIG. 8 depicts four duplexed receive and transmissionbands 804 a-d, 802 a-d, respectively, plus an additional standalonetransmission band 806. The subset of transmission bands 802 a-d, 806 aredifferent from the subset of receive bands 804 a-d.

The receive and transmission bands 804 a-d, 806, 802-a-d supported bythe central unit may be distributed for use among the remote units. Forexample, while all of the remote units may support communicating usingall four receive bands 804 a-d, the transmitting remote units maycommunicate subsets of the overall transmission bands 802 a-d, 806. Someremote units may communicate using a single transmission band 802, someremote units may communicate using multiple transmission bands 802 a-d,and some remote units may share two bands (so that those two bands aresupported by two transmitters). For example, one transmitter remote unitmay be allocated transmission bands 802 a-b, while a second transmitterremote unit may be allocated transmission bands 802 c-d.

FIG. 9 depicts a block diagram of an example of a DAS with remote unitsallocated the different frequency bands that are shown in FIG. 8. Asshown in FIG. 9, four remote units 904 a-d can be coupled to centralunit 902. Each of the remote units 904 a-d is shown configured as atransmitter and a receiver. The number of bands, rather than the numberof antennas or units, may be unequally distributed between receiving andtransmitting. For example, remote unit 904 a may support transmissionband 802 a and all four receive bands 804 a-d. Remote units 904 b, 904 cmay support transmission bands 802 b, 802 c and all four receive bands804 a-d. Remote unit 904 d may be allocated transmission bands 806, 802d and all four receive bands 804 a-d. As shown, transmission bands 802b, 802 c can be supported by multiple remote units (e.g., remote units904 b, 904 c).

While aspects for unequal allocation of frequency bands were discussedwith reference to FIGS. 8 and 9, unequal allocation of frequency bandsamong remote units can apply to any of the DAS configurations shown inFIGS. 2-7. For example, while the remote units 904 a-d shown configuredas both transmitters and receivers for illustrative purposes, remoteunits 904 a-d can also be configured as either transmitting remote unitsor receiving remote units. In such a configuration, the transmittingremote units may utilize the subset of the supported transmission bandsand the receiving remote units may utilize the subset of the supportedreceiver bands. Also, in such a configuration, the subset oftransmission bands can be divided among the transmitting remote units.One transmitter remote unit may be allocated transmission bands 802 a-b,while a second transmitter remote unit may be allocated transmissionbands 806, 802 c-d.

Either or both subsets of receiver and transmission bands can beallocated, as desired, to single, multiple, or all remote units. Thisallocation may be performed based on many different criteria. Forexample, the allocation of receiver and transmission bands among remoteunits may be made to take advantage of the different propagation delaysinherent in the different frequency bands. The allocation of receiverand transmission bands among remote units may also be made to allocatecertain frequency bands where needed depending on user equipment devicecongestion in a coverage area. Further, the allocation of receiver andtransmission bands among remote units may be made to optimize differentcommunication standards being used (e.g., certain frequency bands maycarry carrier signals for LTE cellular systems while other frequencybands may carry carrier signals for W-CDMA cellular systems. As anotherexample, the allocation of receiver and transmission bands among remoteunits may be made to mitigate interference (e.g., from other remoteunits, from other internal systems/networks, or from outside systems).

The allocation of receiver and transmission bands among remote units mayalso be made to better contain the DAS-communicating user equipmentdevices within the network. For example, if an external base station notconnected and outside the coverage area for the DAS is particularlystrong in one area, the external base station may transmit signals thatinterfere with signals used within the DAS. The receiver andtransmission bands can be allocated to mitigate interference with theexternal signals. This allocation can be standardized, optimized atinstallation, or reviewed based on performance, usage, or otherstatistics, or automatically adjusted based on performance, usage, orother statistics.

Another possible advantage of unequal allocation of transmitters andreceivers, in some examples, is the ability to provide different levelsof MIMO capability. For example, a DAS configured in one MIMO format caninclude four downlink transmitters and two uplink receivers. In anotherexample, a multi-band system can include a dynamic MIMO configuration. Adynamic MIMO configuration can include, for example, a scenario in whichsix downlink transmitters are initially available to serve two downlinkMIMO bands. At another time, four of the six downlink transmitters canbe allocated to transmit signals in transmission band A while theremaining two transmitters can be allocated to transmit signals intransmission band B. At yet another time, two of the four transmittersallocated to transmission band A can be reassigned from transmissionband A to transmission band B, thus providing four transmittersconfigured to transmit signals in transmission band B. Dynamicallyreassigning or reallocating transmitters and receivers to transmit indifferent bands can be performed on an entire band or on individualchannels within a band.

FIG. 10 is a flowchart depicting an example of a process 1000 forcommunicating signals in a DAS with unequal receiver and transmitterdistribution. The process 1000 is described herein with reference toFIG. 2, but other configurations are possible. A central unit 202 cantransmit downlink signals to a number of transmitting remote units, 206a-i, as shown in block 1002. Further, each of the transmitting remoteunits 206 a-i can be allocated a subset of frequency bands astransmission frequencies. For example, as discussed above with respectto FIGS. 8 and 9, the transmission frequencies can be split andallocated among the transmitting remote units 206 a-i (e.g.,transmitting remote units 206 a-c may be allocated transmission bands802 a-b and transmitting remote units 206 d-i may be allocatedtransmission frequencies 802 c-d).

In response to receiving downlink frequencies from the central unit 202,transmitting remote units 206 a-i can transmit the downlink signals touser equipment devices, as shown in block 1004. Each of the transmittingremote units 206 a-i can transmit downlink signals, for example, to userequipment devices located within a respective coverage zone.

In block 1006, the central unit 202 can receive uplink signalstransmitted by the user equipment devices from a number of receivingremote units 204 a-d. To achieve unequal transmitter/receiverdistribution in the DAS, the number of receiving remote units 204 a-dmay be different from the number of transmitting remote units 206 a-i.In response to receiving the uplink signals from the receiving remoteunits 204 a-d, the central unit 202 may combine the received uplinksignals and transmit the combined uplink signal to a base station.

Transmitting remote units and receiving remote units can include varioustypes of circuitry or components. For example, the transmitting remoteunits and receiving remote units can include signal processing circuitryfor manipulating signals provided between the central unit 102 and userequipment devices. A remote unit configured as a transmitting remoteunit can include baseband and signal processing circuitry dedicated toprocessing downlink communication signals from the central unit 102 fortransmission to user equipment devices. Similarly, a remote unitconfigured as a receiving remote unit can include baseband and signalprocessing circuitry dedicated to processing uplink communicationsignals from user equipment devices for transmission to the central unit102. In other examples the remote units do not include circuitry forperforming baseband processing. In other examples, the remote units donot include circuitry for performing digital processing.

FIG. 11 depicts an example of circuitry or components that can beincluded in a receiver remote unit 1150 and FIG. 12 depicts an exampleof circuitry or components that can be included in a transmitting remoteunit 1250, but other configurations are possible.

The receiving remote unit 1150 can include a signal processing section1120 with an input amplifier 1102, a down-converting mixer 1104, abandpass filter 1106, and an analog-to-digital (A/D) converter 1108. Theinput amplifier 1102 can amplify the uplink RF bands received frommobile devices in a coverage area. The RF bands may carry communicationinformation for cellular carriers. The down-converting mixer 1104 candown-convert the RF bands to an intermediate frequency using a mixingfrequency f. The bandpass filter 1106 can filter the RF bands at theintermediate frequency. The A/D converter 1108 can convert the filteredRF bands at the intermediate frequency according to a selected samplerate to digital signals.

The receiving remote unit 1150 can also include a channelizer section1130 that includes down-converting channel modules 1116 a-n. Each of thedown-converting channel modules 1116 a-n can correspond to a particularcommunication channel included in the uplink communications signals ofthe uplink RF bands. The down-converting channel modules 1116 a-n candemodulate the digital signals received from the A/D converter 1108 toI/Q samples using I and Q mixers and numerically controlled oscillators(NCOs). The I/Q outputs of the down-converting channel modules 1116 a-ncan be digital signals sampled at a certain sample rate. In an exampleof a receiving remote unit 1150 including seven active channels, sevensets of I and Q data streams can be multiplexed and transmitted to thecentral unit.

The transmitting remote unit 1250 of FIG. 12 can include a channelizersection 1230 with up-converting channel modules 1218 a-n and summers1220-1222. Each up-converting channel module 1218 a-n can be associatedwith a particular communication channel included in downlink digitalcommunication signals received from the central unit. The up-convertingchannel modules 1218 a-n can filter and interpolate the receiveddownlink communication signals per channel to digital signals usingchannel filters, up sample lowpass filters, and complex mixers. Thesummers 1220, 1222 can add the outputs of the up-converting channelmodules 1218 a-n and provide the summed digital downlink signals to asignal processing section 1240.

The signal processing section 1240 can include a digital-to-analogconverter (D/A converter) 1210, an up-converting mixer 1212, and anoutput amplifier 1214. The D/A converter 1210 can convert the digitaldownlink signals to an analog RF signal at an intermediate frequency.The up-converting mixer 1212 can up-convert the analog RF signal at theintermediate frequency to an RF signal using a mixing frequency, whichmay be the same as or different from the mixing frequency used by thedown-converting mixer 1104. The output amplifier 1214 can amplify theup-converted RF signal for output as an RF band to one or more mobiledevices in a coverage area.

The foregoing description of the examples, including illustratedexamples, of the invention has been presented only for the purpose ofillustration and description and is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Numerousmodifications, adaptations, and uses thereof can be apparent to thoseskilled in the art without departing from the scope of this invention.The illustrative examples described above are given to introduce thereader to the general subject matter discussed here and are not intendedto limit the scope of the disclosed concepts.

What is claimed is:
 1. A distributed antenna system, comprising: acentral unit configured to be coupled to a base station, wherein thecentral unit is configured to receive downlink signals from the basestation, wherein the central unit is configured to support a pluralityof transmission bands and a plurality of receiver bands; and a pluralityof remote units configured to communicate wireless signals in a coveragearea of the distributed antenna system, wherein the plurality of remoteunits are communicatively coupled to the central unit and locatedremotely from the central unit; and wherein the distributed antennasystem is configured to mitigate interference using dynamic allocationof at least one of the plurality of transmission bands and/or at leastone of the plurality of receiver bands among the plurality of remoteunits.
 2. The distributed antenna system of claim 1, wherein thedistributed antenna system is configured to mitigate interference usingdynamic allocation of the plurality of transmission bands and theplurality of receiver bands among the plurality of remote units.
 3. Thedistributed antenna system of claim 1, wherein the dynamic allocation ofat least one of the plurality of transmission bands and/or at least oneof the plurality of receiver bands among the plurality of remote unitsis based on propagation delay of the bands.
 4. The distributed antennasystem of claim 1, wherein a source of the interference is internal tothe distributed antenna system.
 5. The distributed antenna system ofclaim 4, wherein the source of the interference is a first remote unitof the plurality of remote units.
 6. The distributed antenna system ofclaim 1, wherein a source of the interference is external to thedistributed antenna system.
 7. The distributed antenna system of claim6, wherein the source of the interference is a base station notconnected to the distributed antenna system and outside the coveragearea of the distributed antenna system.
 8. The distributed antennasystem of claim 1, wherein the dynamic allocation of at least one of theplurality of transmission bands and/or at least one of the plurality ofreceiver bands among the plurality of remote units is based on one ormore statistics associated with the distributed antenna system.
 9. Thedistributed antenna system of claim 1, wherein the dynamic allocation ofat least one of the plurality of transmission bands and/or at least oneof the plurality of receiver bands among the plurality of remote unitsis based on user equipment device congestion in the coverage area of thedistributed antenna system.
 10. The distributed antenna system of claim1, wherein the dynamic allocation of at least one of the plurality oftransmission bands and/or at least one of the plurality of receiverbands among the plurality of remote units is automatic adjusted based onperformance or usage.
 11. The distributed antenna system of claim 1,wherein at least one remote unit of the plurality of remote units isconfigured to support fewer transmission bands of the plurality oftransmission bands than receiver bands of the plurality of receiverbands.
 12. The distributed antenna system of claim 1, wherein at leastone remote unit of the plurality of remote units is configured to onlytransmit wireless signals in the coverage area.
 13. The distributedantenna system of claim 1, wherein at least one remote unit of theplurality of remote units is configured to only receive wireless signalsfrom the coverage area.
 14. A method, comprising: transmitting, by acentral unit of a distributed antenna system, downlink signals to aplurality of remote units of the distributed antenna system, wherein thecentral unit is configured to support a plurality of transmission bandsand a plurality of receiver bands; transmitting, by the plurality ofremote units of the distributed antenna system, the downlink signals toone or more coverage areas of the distributed antenna system; receiving,at the central unit, uplink signals transmitted by user equipmentdevices from the plurality of remote units of the distributed antennasystem; mitigating interference using dynamic allocation of at least oneof the plurality of transmission bands and/or at least one of theplurality of receiver bands among the plurality of remote units.
 15. Themethod of claim 14, wherein the dynamic allocation of at least one ofthe plurality of transmission bands and/or at least one of the pluralityof receiver bands among the plurality of remote units is based onpropagation delay of the bands.
 16. The method of claim 14, wherein thedynamic allocation of at least one of the plurality of transmissionbands and/or at least one of the plurality of receiver bands among theplurality of remote units is based on one or more statistics associatedwith the distributed antenna system.
 17. The method of claim 14, whereinthe dynamic allocation of at least one of the plurality of transmissionbands and/or at least one of the plurality of receiver bands among theplurality of remote units is based on user equipment device congestionin the one or more coverage areas of the distributed antenna system. 18.The method of claim 14, wherein the dynamic allocation of at least oneof the plurality of transmission bands and/or at least one of theplurality of receiver bands among the plurality of remote units isautomatic adjusted based on performance or usage.
 19. The method ofclaim 14, wherein mitigating interference using dynamic allocation of atleast one of the plurality of transmission bands and/or at least one ofthe plurality of receiver bands among the plurality of remote unitsincludes mitigating interference that is internal to the distributedantenna system.
 20. The method of claim 14, wherein mitigatinginterference using dynamic allocation of at least one of the pluralityof transmission bands and/or at least one of the plurality of receiverbands among the plurality of remote units includes mitigatinginterference that is external to the distributed antenna system.